Process for making bowling pins



9 YR. c. CLARK ETAL 2,446,213

- PROCESSEDR MAKING BOWLING PINS Filed Oct. 8, 1946 FJLPI C. CLARAMD 198k 5. (LAP/r Patented Aug. 3, 1948 p 2,446,213. r 'rnooass Fon- BQW'EING' PINS? l Ralph. (3.. ClarkrYenturaandiRay ErClark v wui wbrook oaua n Ap-plilcation ctober 8, 194 6, SerialNo. 7 02;046-

l-Claims (curs -59) .Qurinuentionxrelates; to. a, newandr improved process. for making bowling, pins; l

It is: wellzknotvn that bowling, pins made entimely of Wood are subject; tcr hard wear and. due to-thepimpact ot'bowling balls and hard Wood bowling: alleys. 'The pins become nicked. and gong-ed, especiallyat and around: their bottom standing surface, thus making it diiiicult and often impossible to; stand such wornpins upright on the-alley surface; Worn pins also become unbalanced due. to; such wear and. are therefore obnoxious. and. undesirable to.- proiessional as wellasamateurbowlers v H In ,view at the foregoing we have; developed a new and improved process iormmaking bowling pins having a rubber base or bottom. v t

A complete understanding of our process will be had, from, the; following detailed description and claims of the same taken in conjunction with the annexed drawings where: like-.parts are indicated by like reference characters and where- Figure 1 is a side elevation partly in section of a typical bowling. pin. showing the necessary undercutting of the pin base prior to the insertion of the rubber.

Figure 2 isa bottom plan view showing a wooden bowling pin incomplete j in formand showing the concaved bottom having a centrally disposed hollow opening with a plurality of openings extending radial-lytherefrom 1 Figure 3 is'a vertical section ofa heating mold showingth-e' aforementioned incomplete bowling pin have the bottom opening filled with uncured rubber and being heated.

Figure 4 indicates in vertical section a mold of the shape of a given bowling pin and containing the desired amount of rubber to be molded to the wooden pin in order to form its base.

Figure 5 shows the wooden bowling pin in the mold and the said rubber bottom being molded to the same by means of temperature and pressure.

Figure 6 is a side elevation partly in section of a bowling pin having a rubber base formed by means of our new process hereinafter described.

In manufacturing a bowling pin with a rubber base it is important that a type of rubber composition be selected so as to impart to the completed product the properties found in the conventional all wooden pin. Such properties are weight, balance, and elasticity.

In our improved process a conventional type wooden bowling pin is formed minus the amount of base section desired to be formed of rubber; said incomplete wooden pin is then provided with a concaved bottom surface having a centrally disposed or located: hollow. opening: Wl'llhifllJDIllrality' ofigrooves extending: radially therefrom. In Figures 1 and 2: reference character '=indiscates, the main body of the pin, 2" indicates; time centrally disposed bottom hole, and 3 the. radial grooves as to hole 2. V 1

The main body of. the twooden bowling, pin haying been prepared asaabove indicated; raw or non-cured rubber of desirable composition to give the desired properties is cut from desirable stock so as toi'ill. andlcompletelypack the said bottom openings. 2 and 3. Said bottom section of the pin. containing thehinserted non cured rubber is, then preheatedin a. suitable container or mold to a temperature ranging from 200. degrees. Fahrenheit. to, 350. degrees. Fahrenheit in order that. the inserted rubber may become soit, pliable or plastic. Said temperature. depends upon the. compositiom of the rubber to be used the. pin base... This. called the pro-heating. opleration".. I K

Figure, 3 indicates the pro-heating operation and referen ce ,character 4' indicates the: rubber in the, radial" grooves 3', 5' indicates the rubber in the bottom'central hole land 6 any desirable mold for pro-heating;

A forming mold 1 is prepared and so designedas to formfthe desilr'ed' shape of the piribottom, and in this mold. I is' placed a predetermined amount of nonecuredirubberill this amount. be -l ing' equal to the amount necessary to iormthe base of a completed bow1ing"'pin'.The prede termined amount of rubber 8 contained in the forming mold 1 indicated in Figure 4 is heated to a temperature between and 350 degrees Fahrenheit until the mass is molten and plastic. The exact temperature required depends upon the composition of rubber being used. The incomplete pin after being preheated and containing inserted rubber 4 and 5 in a pliable state is then placed in the forming mold 1 containing the rubber '8 to form the pin base as indicated in Figure 5. The temperature is raised, depending on the composition of the rubber used, in order to have all the rubber in a molten state and to facilitate vulcanization of the two bodies of rubber, namely that contained in the pin base and that contained in the forming mold 1. The pin I is then placed under increased pressure by any suitable means, and the temperature increased to the vulcanizing temperature. Under these conditions of temperature and pressure the rubber is allowed to cure for a length of time depending upon the composition of the rubber.

of 290 to 300 degrees Fahrenheit, and a curing pressure of 500 pounds per square inch. Our rehaving a rubber base, the steps comprising forming said pin with an undercut bottom having a centrally-disposed hollow opening and a plurality of radial grooves extending therefrom, inserting non-cured rubber in said opening and groves. pre-heating the said bottom to a temperature ranging from 200-degrees to 350-degrees Fahrenheit to convert the thus-inserted rubber to a pliable state forming a,sepa'rate molten body of non-cured" rubber in amount suflicient to form the base of said pin, placing said pre-heated botsultant product is a very durable, serviceable, and

practical bowling pin of an improved type.

It is imperative that a proper rubber compo-' sition be selected, of a type capable of being molded to wood, that does not mark or deface the bowling alley floor, that responds to impact substantially as does wood, and in its moldedfor'm' must weigh s bstantially that of wood per unit volume. 1 I What we claim as ourinvention is: 1; In a process of making awooden bowling pi having a rubber base, the steps comprising forming said pin with a concave bottom having a plurality of radial grooves, inserting non-cured rubber in said bottom end grooves, pre-heating said 7 bottom to a temperature sufficient to convert the thus inserted rubber to a pliable state, forming a separate body of non-cured rubber in amount suflicient to form the base of said pin, placing said pre-heated bottom upon said molten body, and subjecting the thus-assembled bottom and molten body to an elevated temperature and pressure to form a cured rubber base attached to said concave bottom of the pin. 2. In a process of making a wooden bowling pin having a rubber base, the steps comprising forming said pin with an under-cut bottom having a centrally-disposed hollow opening and a plurality of radial grooves extending therefrom, inserting non-cured rubber in said opening and grooves, pre-heating said bottom to a temperature sufiicient to convert the thusinserted rubber to a pliable state, forming a separate molten body of non-cured rubber in amount sufilcient to form the base of said pin, placing said preheated bottom upon said molten body, and subjecting the thus-assembled bottom and molten tom upon said molten body, and subjecting the thus-assembled bottom and molten body to a temperature ranging from ZOO-degrees to 350-de- 'grees Fahrenheit and a pressure of SOD-pounds per square inch to form a cured rubber base attached to said undercut bottom of the pin.

M 4. In a process of making a wooden bowling pin ha'vinga rubber base, the steps comprising forming said pin with an undercut bottom having a centrally-disposed hollow opening and a pmrality of radial grooves extending therefrom, in-. serting non-cured rubber in said opening and grooves, pre-heating the said bottom to a temperature ranging from 270-degrees to 28Q-degrees Fahrenheit to convert the thus-inserted rubber to a pliable state, forming a separate molten'body of non-cured rubber in amount sufiicient to form the base of said pin, placing said pre-heated bottom upon said molten bodyj-and' subjecting the thus-assembled bottom and molten body to a temperature rangingfrom 290-de grees to 300-degrees Fahrenheit and a pressure of Q-pounds per square inch to form a cured rubber base attached to said undercut bottom of thepin. RALPH C; CLARK.

RAY CLARK. I

- REFERENCES CITED,

The following references are of record in the file of this patent: v

UNITED STATES PATENTS 1,895,738 Shugg Jan. 31, 1933 

